Papers by Keyword: Indoor Air Quality

Abstract: Airborne transmission of pathogens, particularly through respiratory droplets and aerosols, poses a significant risk to human health and contributes to the spread of infectious respiratory disorders. Urbanization and population increase are frequently linked to rising energy consumption and the use of natural resources like fossil fuels, which harms the ecology. Solar and geothermal energy are examples of renewable energy sources that provide options that can help with environmentally friendly and cost-effective energy-efficient thermal comfort solutions. Adequate ventilation plays a crucial role in mitigating this risk and safeguarding human well-being. Previous studies have examined the importance of ventilation in airborne infection control, emphasizing its impact on indoor air quality. This paper aims to comprehensively review various control measures for enhancing indoor air quality, taking into account relevant influencing parameters. Additionally, the study explores sustainable solutions that can contribute to the long-term prevention of declining air quality and mitigate the potential impact of future biological threats on human health. A thorough literature study evaluates the performance of protected zone ventilation in reducing the risk associated with respiratory droplets and aerosols generated by infected individuals in different confined spaces. The findings highlight the significance of guideline recommendations to prevent airborne transmission of infections and offer a concise overview of enhanced ventilation strategies for improving indoor air quality, particularly in air-conditioned environments. The results of this review contribute to a deeper understanding of the effectiveness of protected zone ventilation in reducing the spread of respiratory pathogens. Moreover, they provide insights into the importance of maintaining optimal indoor air quality through appropriate ventilation measures. The implications of this research are crucial for developing evidence-based guidelines and strategies that can mitigate the impact of airborne transmission and foster healthier indoor environments.

Abstract: People spend most of their time in various indoor spaces and their health is exposed to different kinds of air pollutants. Volatile organic compounds (VOCs) belong to a group of chemical substances polluting the indoor environment. They come into the interior of buildings mainly from internal sources in the form of building materials, flooring, composite wood products, adhesives and other consumer products. Their presence in indoor air is monitored, due to their carcinogenic and mutagenic effects on human health. Many studies of indoor environment contaminated by VOC have been published during the last years. The present study provides general overview of the occurrence and emission sources of VOCs in the indoor environment of different types of buildings. The most frequently monitored indoor organic pollutants in terms of their occurrence and health risk are BTEX (benzene, toluene, ethylbenzene and xylenes), terpenes (α-pinene and d-limonene) and aldehydes (formaldehyde, acetaldehyde and benzaldehyde). Their concentrations in different indoor environments are variable and depend on factors such as emission characteristics of sources, microclimatic and ventilation conditions. Formaldehyde and toluene levels increased significantly with increasing room temperature. Benzene enters the indoor environment of buildings from external sources, especially from traffic or industrial areas. Formaldehyde, α-pinene and d-limonene originate from indoor sources as a part of building materials, furniture and household products.

Abstract: Natural ventilation is currently widely used in existing buildings in order to assure the fresh air needed by occupants. The low investment and operational costs are the most important advantages of this type of ventilation. However, the dependency on the meteorological parameters has to be considered as disadvantage of the natural ventilation. In case of buoyancy-driven ventilation, the variation of the outdoor temperature results in the variation of the infiltrated air flow, CO₂ concentration in the indoor air and energy demand of the ventilation. The air inlet and outlet orifices have to be properly chosen in order to meet the indoor air quality and energy requirements at the same time. In this paper the CO₂ concentration and energy aspects of gravitational ventilation are discussed in case of a typical block of flats.

Abstract: This paper presents a CFD analysis on thermal comfort and indoor air quality affected by partitions in an air-conditioned building. CFD experiments are carried out to simulate variables of indoor air before/after installation or removal of partitions. Accordingly, the Predicted Mean Vote (PMV) is determined as an indicator of thermal comfort while the carbon dioxide concentration within an air-conditioned space is used for the assessment of indoor air quality. Some simulated results are validated by measurements with good agreement where a case study is conducted in an air-conditioned space of a library. With the proposed methodology, it can be recommended in a case study that the significant effects of partition on thermal comfort are observed where the area with neutral sensation and slightly-cool sensation reduces significantly. The occupants feel uncomfortably cold after installing partition. The carbon dioxide concentrations slightly increase in some areas but the average concentration remains acceptable according to ASHRAE standard. Without the reinforcement of the air-conditioning units, the installation of partition at the desired location is not encouraged regarding to occupant’s thermal comfort and indoor air quality.

Abstract: Disposal of industrial mosaic sludge waste into landfills has become serious threat to the global environment due to the huge generation of waste every year. Nevertheless, a relevant alternative solution could be develop as recently rapid growing interest are focusing on the usage of wastes material into the manufacturing of fired clay. Furthermore, previous research has successfully incorporated different types of sludge into the fired clay brick. Therefore, this study is focusing on the potential of incorporating two types of mosaic sludge in terms of properties and indoor air quality (IAQ) performance. Different percentages (0%, 5%, 10%, 20%, 30%) of mosaic sludge waste were incorporated into fired clay brick. In terms of strength, 30% of sludge waste show higher strength of brick. In terms of IAQ, all the results of both sludge waste were compiled with the standard requirement. From this study, it shows that mosaic sludge that incorporated with fired clay brick is safe to be used towards the environment since it is complied with ICOP-IAQ. In addition, this study may help to create an alternative method to dispose the sludge waste as well as to provide another low cost material for the clay brick.

Abstract: It is well known that wool carpets and upholstery permanently remove many gaseous pollutants from the air, thus improving indoor air quality, and peoples’ wellbeing. The aim of the work reported here was to develop wool-based filters that could be used in homes and offices to improve indoor air quality. The abilities of wool, jute, and some other materials used in building interiors, to absorb common indoor air pollutants, formaldehyde, sulphur dioxide and nitrogen oxides were compared. Testing was conducted in a chamber that reproduced the conditions found in a typical room. Wool and jute were found to give high levels of absorption and the results were used to design six types of wool-based filters that were intended to be compact, with high rates and capacities of absorption. The filters were passive, relying on high surface areas and diffusion, rather than forced air circulation, thus minimising their net environmental impact. Filters based on wool yarn, roving, balls and unbacked carpet, were all very effective, absorbing between 94 and 96% of the air pollutants over six hours. This study has shown that wool-based passive filters can significantly improve indoor air quality, and represent a new use for wool.

Abstract: Good indoor environmental quality (IEQ) is desired for a healthy indoor environment. The microbial growth in indoor environments contribute into poor indoor environmental quality can cause various of health problems. Antimicrobial coatings are designed to generate a surface that is easy to clean and can also incorporate active agents, commonly called biocides, which prevent microbial colonization, the subsequent growth and bio-deterioration of the substrate. The aim for this study is to treat indoor environmental quality in buildings by reviewing the possible application of potassium sorbate used in food industry preservatives to be use as indoor antimicrobial. Plasterboard wall was used as a substrate to see the influence of different common wall finishing used such as paints and wallpapers on fungal growth. Potassium sorbate was tested against fungal isolated from affected room M146, FKAAS building. The total fungal counts in affected room was 806 cfu/m³. The ASTM D5590-00 standard was used to evalute fungal growth and potassium sorbate was effective to inhibit the amount of fungal growth on four common types of wall finishing used on plasterboard wall. As a result, the percentage reduction in growth between control and treatment sample were 10% on thin wallpaper, 15% on acrylic paint, 25% on glycerol-based paint and 60% on thick wallpaper.

Abstract: Malaysia is located on the equator has resulted in having two seasons wet and dry. Both of the seasons can influence indoor air quality of buildings promoting the growth of fungal. Fungal growth can occur with the combinations of temperature, relative humidity, substrate and others. Indoor and outdoor air quality is essential for building occupants to prevent the infection diseases caused by fungal. The goal of this study is to remediate the growth indoor fungal after treated with biocides on different types of wall finishing and evaluate the efficiencies of biocides to treat indoor fungal. In this study, the biocides are utilized as a coating for coating bio-resistance. The measurements of the fungal growth are made by growing the samples on realistic wood substrates on the different wall finishing such as paints and wallpapers. The mold that grew are affecting most of the rooms is selected. The air sampler that have been used to isolate the samples of indoor fungal according to NIOSH Manual Analytical Method (NMAM 0800), a guideline provided by National Institute of Occupational Safety and Health (NIOSH). The fungal growth was evaluated using the ASTM D5590-00 standard measuring on the surface of substrate. The results show that potassium sorbate as biocide was able to reduce the indoor fungal growth depending on the type of material used in the building.

Abstract: Recently waste material pollution is a critical issue in every developing country. The factors such as increasing of growing population, daily and industrial activities will lead to these phenomena. These issues give an idea to use waste as a construction material that will give minimum impact towards the environment. Many researchers have been studied on waste material such as organic waste, sludge, fly ash, rice husk and processed waste tea into fired clay brick. In this study, the investigate on the incorporating of cigarette butts (CBs) was conducted. During this study, different percentages of CBs (0%, 2.5% and 5.0%) were added into fired clay brick. Meanwhile, different heating rates were applied during the firing stage, which are 1°C/min, 3°C/min and 5°C/min respectively. All samples were fired up to 1050°C. Leaching tests were carried out to investigate the possibility of heavy metals leached from the manufactured brick. The results demonstrated that, in terms of physical and mechanical properties, CB Brick (2.5%) at 1°C/min improved the most and leached low heavy metals. For IAQ test, CB Brick (2.5%) fired at 1°C/min is acceptable to be used as building materials since it complied with ICOP-IAQ.

Abstract: In order to improve indoor air quality, the interest in and the use of sorptive building materials that decrease the concentration of an indoor air pollutant have increased. The use of sorptive building materials is one way to decrease the concentration of an indoor pollutant that can adversely affect human health. In this study, we evaluated the effects of sorptive building materials applied to a wall on the decrease in the concentration of toluene emitted from the flooring. We also examined how the air exchange rate of the room, the loading factor of the sorptive materials, and the mass transfer coefficient influenced the sorptive performance; these effects were well reproduced experimentally with computational fluid dynamics (CFD) simulations. The results show that sorptive building materials have a fairly strong effect on the decrease in toluene concentrations in rooms and that this effect can be expected in real-world scenarios.